Rotary cutter type mowing machine



June 8, 1954 Filed Dec. 20, 195i Patented June 8, 1954 UNITED STATES PATENT OFFICE ROTARY CUTTER TYPE MOWIN G MACHINE Hubert H. Montague, Traverse City, Mich. Application December 20, 1951, Serial N 0. 262,516

16 Claims.

The present invention has for its purpose to improve the construction and operation of the type of small, manually operable mowing machines forming the subject of my prior Patents Nos. 1,317,212 and 1,465,279.

In each such machine there are many pairs of cooperating, rotary shearing cutters, each pair constituting a separate shearing unit. One of the disadvantages of the prior construction has been the inability to adjust the cutters in each unit to compensate for wear; so that replacements must be made after a certain amount of wear, in order to obtain sharply cutting shears.

A main object of the present invention is to modify the construction of the shearing units that the user may easily make adjustments to compensate for wear and maintain the mower in good cutting condition.

In carrying out the aforesaid objects a construction has been achieved that possesses the further advantages of better shearing action and freedom of clogging due to failure of cut grass to pass through the machine or tendency to wind around rotary parts. Therefore, the present invention may be said to have as subsidiary objects the attainment of these added advantages.

The various features of novelty whereby the present invention is characterized will hereinafter be pointed out with particularity in the claims, but, for a full understanding of the invention and of its objects and advantages, reference may be had to the following detailed description taken in connection with the accompanying drawing, wherein:

Figure 1 is an end elevation of a lawn mower, including a fragment of the handle, embodying the present invention; Fig. 2 is a front elevation of a fragment of the mower, viewed from line 2-2 of Fig. 1; Fig. 3 is a view looking up from line 3-3 of Fig. 2, showing only the rotary cutters,

together with one of the toothed ground wheels; Fig. 4 is a top plan view of the parts shown in Fig. 2, the handle being omitted; and Fig. 5 is a sectional view on line 5-5 of Fig. 4.

In the drawing, I represents a long, horizontal frame consisting of a light metal beam having a web 2, a wide upper flange, in the form of individual ears 3 arranged at right angles to the web and projecting forwardly therefrom, and a narrow lower flange 4 that projects rearwardly. In front of web 2 and below flange 3 is a transverse axle or shaft 5. This shaft is supported at its ends for rotation by bearing pedestals 6, of which only one is shown, attached to and'projecting 2 forwardly from web 2. Fixed to and rotatable with the axle or shaft are toothed ground-engaging wheels I, 1; these wheels serving both as rolling supports for the machine and as drives for the cutters in which the present invention resides.

As in my prior machines, each ear 3, excepting the two endmost ears, supports two rotary shearing cuters, one cutter on each ear cooperating with the complementary cutter on an adjacent ear; only one cutter being needed on each of the two endmost ears.

In the specific arrangement shown, each shearing unit comprises a disc element 8 having a chamfered shearing edge 9, an inverted, frustoconical cup-shaped element ID that liesabove and in slightly overlapping relation to the disc, and means to cause grass to be gathered and fed between the cooperating shearing edges.

Each shearing disc underlies one of the ears 3 and protrudes from one side thereof; whereas each shearing cup overlies its supporting ear and projects beyond one side of the latter to come into operative relation to the complementary disc.

Each disc is held in place by a screw II that passes down through an ear 3 and an antifriction bushing [2 in the disc. A nut I4 on the lower end of the screw clamps the bushing tightly against the ear, while leaving the disc free to revolve.

Lugs i5 are formed on the under side of the disc by a punching operation. These lugs are designed to mesh with the teeth on an adjacent ground wheel 1; whereby the disc rotates whenever the mower is run over the ground. The disc also is provided with peripheral, radial projections l6, spaced far apart, to gather grass and draw it into the shearing zone.

Each cup shear element is part of a special assembly mounted on a post rising from the correspending supporting ear. This post is a headed bolt or screw I! screwed into and rising from the ear, together with an anti-friction bushing l8 surrounding the bolt or screw. Surrounding the post is a headed tubular member I9 that extends down through the bottom wall of the cup and is screwed into a grass gathering spider 20. Surrounding part 19, within the cup, is a short, loose sleeve 2| that serves as a spacer between the spider and the bottom wall of the cup. In making the assembly, parts 10, 20 and 2| are first secured together into a rigid whole by tubular member [9. The post is then inserted and screwed into the ear. To allow the shear element and grass gathering combination to be freely rotatable, bushing 18 is made long enough to pr vent fixedly clamping such combination against the frame.

The spider 28 consists of a circular central section 22 from w ich radiate long curved fingers 23, the fingers being preferably pointed at their ends. The diameter of the spider is substantially greater than that of disc 8, so that there is a greater overlapping of the disc and the spider than of the disc and cup shearing element.

The parts are so proportioned and arranged that each spider lies directly below disc while the cup shearing element, t'o-which thezspiderris fastened, lies above and in contact with the same disc. The spider fingers extend into the-path of the lugs on such disc sothat; as thedisc re.-- volves, it also drives the spider and cooperating cup shearing element.

The spider fingers are so curved that their advance long-edges are concave, thereby enabling them-to keep grassfromslipping ollftheends. of the fingers as the grass is being swept between theshearing edges.

Sinceithe, circumferential lengths of the: shearing edges in each pair of cooperating cutters differ substantially from each other, the shearing is: done with a. distinct slicing action that makes the. shearing mechanism very efficient. This-slicing effect is augmented by the fact that there are more fingers onthe spider than there are lugs on the disc. This causes the spider'to rotate at a lesser angular speedthan the disc.

i By using a cup for one of the two cooperating shearing elements, the other element may be a disc without fear that grass will clog the machine, either by Winding aboutsorne rotating part or by failure of cuttingsto dropout. The projections on the periphery of the disc; since they extend'almosttothe spacers 2A, helpin clearing away the cuttings; and, if their advance radial edges are sharpened, they will-cut up heavy grass and little stickswhichchoke ordinary'machines.

One of the important features of the invention is making possible to maintain good-contact between the two shearing members of each pair. Ifsuch contact is lost, due towear, theshearing action becomes ragged and unsatisfactory. With my construction, however, as soon as thereis evidence of wear, one need only remove the; bolt or screw 1?, unscrew tubular part i8, so asto beable totake out thespacingsleeve 21. After the sleeve has been: shortenedslightly;.by filing or grinding, the parts'are reassembled, withthe shearing edgesragaininmost efi'ective: shearing r relation to. each other.

In order to permit more than a few sharpenings, it may be necessary tofile or grind the bushing 18 as well asthe spacer; One way of permittingrthis' to be done. is originallyto make the tubular part is shorter than; bushing 13: This allows the'bushing-to bescrewed down farther; to keep: up with the shortened spacer, without protruding from the under side of the spider.

While I have illustrated and described. with particularity only a single preferred form of my invention, I do not desire to be limited to the exact details thus illustrated and described, but intend to cover all forms and arrangements that come within the definitions of my invention constituting the appended claims.

I claim:

1. A rotary grasscuttingassembly comprising two oppositely rotatable shear members positioned one above the: other. and having their axes of rotation spaced apart from each other to bring marginal portions overlapping and in contact with each other, said members being provided with circumferential complementary shearing edges, the shearing edge of said upper member being continuous, radiating grass gathering fingers connected to and rotatable with the upper of said members and lying a substantial distance below the latter and below and in overlapping relation to the lower of the two; members, said lower member having grass gathering projections distributed along the shearing edge, and means to drive such members in a manner to cause the twozshearing edges .to travel at different circumferential speeds.

2; A- rotary grass cutting assembly comprising twoshear. members; oppositely rotatable about parallel axes, positioned one above the other and haviz'ig-marginal portions overlapping and in contact with each other; said members having along said. marginal portions circumf.erential;. comple mentary shearing edges; radiating grass gathering fingers connected: to: and. rotatable; with: the upper of. said members and lying a substantial distance below the latter and below. and overlapping relationto thelower of thetwo members, the upper of. said members being in theqform of an inverted cup having: a. continuous". shearing edge following the rim, and. said lower member being in the form of a disc havingv grass: gathering projections distributed. along the.v shearing edge;

3. A rotary grass cutting assembly; comprising two shear members, oppositely rotatable: about spaced, parallel a es, positioned; one above the other and having marginal portions overlapping and in contact with; each. other; said members having along said marginal. portions; circume ferential, complementary shearing edges. the shearing edge on the upper member'being continuous, the under side. of: said: upper: member being dished across'a diameter onlyslightlyrless than that of the shearing edgethereof," radiatin grass gatheringfingers connected to. and rotatable with the upper of saidmembers and lying a substantial distance below the latter; andibelow and in overlapping-relation to. thelovver of. the two members, and said lower member having grass gathering projections distributed; along the shearing edge.

4. An assembly as set forthin claim 3:, where.- in the projections along the-shearing.edgeoffthe lower. shear member are provided with radial cutting edges.

5. In a mowing machine, a grass cuttingmeans comprising a flat-lying shear disc having a peripheral cutting edge, a cooperating circular member above at one side of, and'having a marginal portion overlapping and in contact with. a marginal. portion of, the disc, the. said circular member having a continuous. cutting edge-,- said disc and said member. being rotatableabout parallel axes, a grass gathering element underlying andflxed to the upper shear member, said element having fingers radial to the axis ofrotation of said upper member and arranged a substantial distance below the latter. andbelow and in overlapping relation to the disc, lugs on the under side of, the disc in positionto' engage with said fingers as the disc revolves and causesaid gathering element and said upper shear member to revolve, and driving means engaging said lugs-to rotate the disc.

6. Agrass cuttingmea-ns: as setforthinclaim 5, wherein there isza difierence. innumberrbe tween the'lugs and the-fingers.

7. In a mowing machine, provided with toothed ground wheels, a grass cutting means comprising a fiat-lying shear disc having a peripheral cutting edge, a cooperating circular shear member above at one side of, and having a marginal portion overlapping and in contact with a marginal portion of the disc, said marginal portion having a continuous shearing edge, said disc and said member being rotatable about parallel axes, a grass gathering element located a substantial distance below and fixed to the upper shear member, said element having fingers radial to the axis of rotation of said upper member and arranged a little below and in overlapping relation to the disc, and lugs on the under side of the disc in position to engage with said fingers as the disc revolves and cause said gathering element and said upper shear member to revolve; the disc with its lugs constituting a toothed wheel meshing with one of the gro'nd wheels to cause the disc to be driven by that ground wheel.

8. In a mowing machine, a grass cutting means comprising a flat-lying shear disc having a pcripheral cutting edge, a cooperating circular shear member above at one side of, and having a marginal portion overlapping and in contact with a marginal portion of the disc, the said circular member having a continuouscutting edge, said disc and said member being rotatable about parallel axes, a grass gathering element underlying and fixed to the upper shear member, said element having fingers radial to the axis of rotation of and a substantial distance below said upper member and arranged a little below and in overlapping relation to the disc, lugs on the under 5 side of the disc in position to engage with said fingers as the disc revolves and cause said gathering element and said upper shear member to revolve, and driving means engaging said lugs to rotate the disc; said fingers being curved in the plane thereof in the direction to cause the concave edge of each finger to be the leading edge while moving in the direction to carry grass into the cutting zone.

9. A shear device for cooperation with a complementary rotary shear device, comprising a circular member in the form of an inverted cup and having a continuous shearing edge following the circumference thereof in the plane of the bottom of such member, a grass gathering device below and coaxial with said member, having fingers radial to the axis of such member and located in a plane parallel to and a substantial distance below the aforesaid plane, a tube extending through the center of said member and screwed through the center of said grass gathering device, a spacing sleeve around said tube between said member and said device, and a head on the upper end of the tube and engaged with said member to secure the several parts into a rigid whole.

10. A device as set forth in claim 9, wherein the sleeve and the cup are two separate pieces.

11. A shear unit for cooperation with a complementary rotary shear element, comprising a member in the form of an inverted, frusto-conical cup having a shearing edge following the circumference thereof in the plane of the cup rim, a grass gathering device located at a substantial distance below said member and having fingers radial to the axis of such member and curved in the same direction at their outer ends in a plane parallel to the aforesaid plane, a tube extending through the center of said member and screwed through the center of said grass gathering device, a spacing sleeve around said tube between said member and said device, a head on the upper end of the tube to engage said member and secure the several parts into a rigid whole; and a fastening means for the unit including a headed screw long enough to extend through the tube and enter a support below the unit.

12. A shear unit for cooperation with a complementary rotary shear element, comprising a circular member in the form of an inverted cup and having a continuous shearing edge following the circumference thereof in the plane of the bottom of such member, a grass gathering device below said member having fingers radial to the axis of such member and in a plane spaced a substantial distance below and parallel to the aforesaid plane, a tube extending through the center of said member and screwed into the center of said grass gathering device, a spacing sleeve around said tube within said member and abutting said device; a head on the tube engaging said member and securing it rigidly to said deviceyand a fastening means for the unit including an anti-friction bushing slightly longer than said tube and having an easy fit in the latter, together with a headed screw long enough to extend through the tube and enter a support below the unit.

13. In a mowing machine of the type wherein pairs of cooperating rotary cutters are mounted on forwardly projecting ears on a transverse frame member, a post fixed to and rising from such an ear, and a rigid shear unit rotatable on the post: said unit comprising a tube surrounding the post, a circular shearing member on the upper end of the tube, and an element on the lower end of the tube having fingers radiating from the tube, with a substantial free space between the shearing member and said element;

said fingered element serving as a grass gatherer and as the final element in a drive for the unit.

14. In a mowing machine of the type wherein pairs of cooperating rotary cutters are mounted on forwardly projecting ears on a transverse frame member, a post fixed to and rising from such an ear, and a rigid shear unit rotatable on the post: said unit comprising a tube surrounding the post, a circular shearing member on the upper end of the tube, and an element on the lower end'of the tube having fingers radiating from the tube, with a substantial free space between the shearing member and said element; said fingered element serving as a grass gatherer and as the final element in a drive for the unit; a disc having a peripheral shearing edge mounted on an adjacent ear and extending into said space in contact and overlapping relation with said circular shearing member, and having, also, grass gathering projections along the shearing edge; and lugs on the disc to engage said fingers and cause said shearing unit to rotate when the disc rotates.

15. In a mowing machine of the type wherein pairs of cooperating rotary cutters are mounted on forwardly projecting ears on a transverse frame member, a disc rotatably mounted more or less horizontally under one such ear and having a peripheral shearing edge with grass gathering projections distributed along said edge, a post fixed to and rising from an adjacent ear, a rigid shear unit rotatable on the postysaid unit comprising a tube surrounding the post, a shearing member in the form of an inverted cup the rim of which is the shearing edge on the upper end eemem of: the; tube; overlapping and; engaged with. the upper: side of said disc,- e,n,-e1ement on theylower end of; the; tube having grass gathering fingers radiating from the tube-ma plane-that isasubstentiel; distance belowthe :said rim and underlying a marginal. portion ofthe disc; and lugsion the under side-of the; disc toengageeaaidrfingers and drive said unit.

16; A combination. as. set forth.- in: claim.- 15 wherein the projections on-thedise. are provided with radial shearing; edges complementary to the; cutting; edge of saidlcircular shearing, meme her;

References; Gitedin; thefile of: this. patent UNITED;- STATES PATENTS Number Name Date. Montague v Sept 30,1919 Montague VAug .V21; 1923 Wallace Apr. 7, 1931 Gardner Aug.v 31;, 1948 Hutchens V No v. 25;,1952 

